English verb conjugation
COULD CERTIFICATE

Regular verb: certificate - certificated - certificated

Affirmation

Simple form	V-ing form
I could certificate you could certificate he could certificate we could certificate you could certificate they could certificate	I could be certificating you could be certificating he could be certificating we could be certificating you could be certificating they could be certificating
Perfect	V-ing perfect
I could have certificated you could have certificated he could have certificated we could have certificated you could have certificated they could have certificated	I could have been certificating you could have been certificating he could have been certificating we could have been certificating you could have been certificating they could have been certificating

Negation

Simple form	V-ing form
I couldn't certificate you couldn't certificate he couldn't certificate we couldn't certificate you couldn't certificate they couldn't certificate	I couldn't be certificating you couldn't be certificating he couldn't be certificating we couldn't be certificating you couldn't be certificating they couldn't be certificating
Perfect	V-ing perfect
I couldn't have certificated you couldn't have certificated he couldn't have certificated we couldn't have certificated you couldn't have certificated they couldn't have certificated	I couldn't have been certificating you couldn't have been certificating he couldn't have been certificating we couldn't have been certificating you couldn't have been certificating they couldn't have been certificating

Interrogative form

Simple form	V-ing form
could I certificate? could you certificate? could he certificate? could we certificate? could you certificate? could they certificate?	could I be certificating? could you be certificating? could he be certificating? could we be certificating? could you be certificating? could they be certificating?
Perfect	V-ing perfect
could I have certificated? could you have certificated? could he have certificated? could we have certificated? could you have certificated? could they have certificated?	could I have been certificating? could you have been certificating? could he have been certificating? could we have been certificating? could you have been certificating? could they have been certificating?

Interro-negative form

Simple form	V-ing form
couldn't I certificate? couldn't you certificate? couldn't he certificate? couldn't we certificate? couldn't you certificate? couldn't they certificate?	couldn't I be certificating? couldn't you be certificating? couldn't he be certificating? couldn't we be certificating? couldn't you be certificating? couldn't they be certificating?
Perfect	V-ing perfect
couldn't I have certificated? couldn't you have certificated? couldn't he have certificated? couldn't we have certificated? couldn't you have certificated? couldn't they have certificated?	couldn't I have been certificating? couldn't you have been certificating? couldn't he have been certificating? couldn't we have been certificating? couldn't you have been certificating? couldn't they have been certificating?